The invention relates to portable work benches or tables which include an integral clamping table or vise. More particularly, the present invention relates to a work table with a clamping table or vise where the vise may be operated with one hand.
Carpenters, woodworkers and handymen which work with wood as well as other materials, often need a work bench or table which may be utilized to hold workpieces. Ordinarily, these work benches include a vise which clamps portions of the table top together to secure the workpiece on the table. One such device is that of the assignee of the present invention which is sold under the WORKMATE(trademark) trademark. These tables are versatile, provide for secure clamping, are compact and are convertible to dual height positions.
The work bench ordinarily includes two vise screws with handles on each one. The vise screws, via the handles, are operated by the user with the user using both hands. While a user may utilize one hand, the user must rotate both handles in order to clamp a workpiece between the clamping table members. Accordingly, it is desirable to utilize one hand to crank both of the vise screws so that clamping of the workpiece may be accomplished by the user using only one hand. By enabling cranking of the vise to clamp the workpiece with one hand, the user is capable of holding the workpiece in place with his other hand. Also, it is desirable that the vise clamp irregular objects while turning the vise screws with one hand.
Accordingly, it is an object of the present invention to provide an improved vise for a work bench which enables the vise to be tightened down utilizing one hand.
In accordance with one aspect of the invention, a work bench comprises a frame; a table surface on the frame, with the table surface including at least two members; one of which is movably coupled with the frame to enable clamping of a workpiece between the two table surface members. A drive mechanism moves the table members with respect to one another. The drive mechanism includes two screws coupled with one of the members. The two screws are spaced from one another to move the table member upon rotation of the screws. A sprocket is coupled with each screw. A transmission belt or chain is coupled with the sprocket to drive the screws together. At least one handle is coupled with one of the screws to rotate the screws. At least one clutch is coupled with at least one screw to limit clamping pressures on the workpiece. The clutch enables rotation of one screw with respect to the other screw so that irregular workpieces may be clamped between the table members and clamping of the workpiece may be accomplished by rotation of the handle by one hand of the operator. The clutch is self-actuating. The clutch includes a spring and a detent removably coupled within slots in a hub of the sprocket. Also, both screws may include a clutch. Further, each screw may include a handle. One of the handles has a different configuration than the other to identify to the user that clamping of the table surfaces may be accomplished by rotation of only one handle to drive both screws.
In accordance with a second embodiment, a work bench includes a frame; a table surface on the frame, with the table surface including at least two members; one of which is movably coupled with the frame to enable clamping of a workpiece between the two table surface members. A drive mechanism moves the table members with respect to one another. The drive mechanism includes two screws coupled with one of the members. The two screws are spaced from one another to move the table member upon rotation of the screws. A sprocket is coupled with each screw. A transmission belt or chain is coupled with the sprocket to drive the screws together. At least one handle is coupled with one of the screws to rotate the screws. At least one clutch is coupled with at least one screw to limit clamping pressures on the workpiece. The clutch enables rotation of one screw with respect to the other screw so that irregular workpieces may be clamped between the table members and clamping of the workpiece may be accomplished by rotation of the handle by one hand of the operator. A guard covers the transmission belt or chain. The guard is coupled with the frame. The guard includes at least one tensioning member unitarily formed with and extending from the guard. The guard includes at least one alignment member to maintain alignment of the belt or chain to the sprocket. A biasing member is associated with the belt or chain to automatically adjust to changes in the belt or chain length to take up slack and provide positive belt or chain tension. The biasing member may be a helical spring. Further, the guard may include two tensioning members as well as two pairs of alignment members, each pair sandwiching a tension member.
In accordance with a third aspect of the invention, a work bench comprises a frame; a table surface on the frame, with the table surface including at least two members; one of which is movably coupled with the frame to enable clamping of a workpiece between the two table surface members. A drive mechanism moves the table members with respect to one another. The drive mechanism includes two screws coupled with one of the members. The two screws are spaced from one another to move the table member upon rotation of the screws. A sprocket is coupled with each screw. A transmission belt or chain is coupled with the sprocket to drive the screws together. At least one handle is coupled with one of the screws to rotate the screws. At least one clutch is coupled with at least one screw to limit clamping pressures on the workpiece. The clutch enables rotation of one screw with respect to the other screw so that irregular workpieces may be clamped between the table members and clamping of the workpiece may be accomplished by rotation of the handle by one hand of the operator. The handle includes a hub, a straight portion extending from the hub, a curved portion extending from the straight portion, and a knob extending from the curved portion. The knob enables rotation of the handle. The curved portion has a truncated U-shape with one end coupled with the straight portion and the knob extending from the other end. The hub has a desired height as well does the straight portion which is less than that of the hub. The curved portion has a height greater than the hub. An end of the curved portion and a side of the straight portion are continuous forming a planar side portion of the handle. A connecting member extends from the hub and is unitary with the straight portion and a portion of the curved portion. The handle may be injected molded from a plastic material.
In accordance with a fourth aspect of the invention, a guard for a work bench drive transmission comprises a first wall, at least one second wall extending substantially perpendicular to the first wall, and at least one guide extending from the first wall. The guide extends transverse to the direction of travel of the transmission belt or chain. Preferably, a second guide extends from the first wall. Preferably, two parallel spaced second walls extend from the first wall. An alignment member extends from the first wall. Preferably, the alignment member is stamped into the first wall and two alignment members sandwich each guide member. Also, a second wall includes a biasing member to provide positive belt or chain tension. The first or second walls include cut-outs to secure the helical spring biasing member to the guard.
In accordance with a fifth aspect of the invention, a handle for operating a movable work bench comprises a hub, a straight portion extending from the hub, and a curved portion extending from the straight portion. A knob extends from the curved portion to enable rotation of the handle. The curved portion has a truncated U-shape with one end coupled with the straight portion and the knob extending from the other end. The hub has a desired height, as well does the straight portion, which is less than the height of the hub. Also, the curved portion has a height greater than the hub. Also, one end of the curved portion and a side of the straight portion are continuous forming a planar side portion of the handle. A connecting member extends between the hub, straight and curved portions, and is unitary with the three. The handle is ordinarily molded from a plastic material.
In accordance with a sixth aspect of the invention, a belt or chain drive transmission for a work bench comprises two screws adapted for coupling with a member to be moved against another member to provide clamping. A sprocket is coupled with each of the screws. A transmission belt or chain is coupled with the sprockets. At least one handle is coupled with one of the screws to rotate the screws. At least one clutch is coupled with at least one screw to limit clamping pressures on a workpiece. The clutch enables rotation of both screws, one with respect to the other which is being directly rotated. The clutch is self-actuating and includes a spring and a detent coupled with a slot in a hub of the sprocket. Preferably, each screw includes a clutch and each screw includes a handle. Also, one of the handles has a different configuration which identifies to the user that only one handle may be rotated to drive both the screws. Also, each screw includes a stop to position the spring with respect to the sprocket.
With respect to a seventh aspect of the invention, a work bench includes a frame; a table surface on the frame, with the table surface including at least two members; one of which is movably coupled with the frame to enable clamping of a workpiece between the two table surface members. A drive mechanism moves the table members with respect to one another. The drive mechanism includes two screws coupled with one of the members. The two screws are spaced from one another to move the table member upon rotation of the screws. A sprocket is coupled with each screw. A transmission belt or chain is coupled with the sprocket to drive the screws together. At least one handle is coupled with one of the screws to rotate the screws. At least one clutch is coupled with at least one screw to limit clamping pressures on the workpiece. The clutch enables rotation of one screw with respect to the other screw so that irregular workpieces may be clamped between the table members and clamping of the workpiece may be accomplished by rotation of the handle by one hand of the operator. A guard covers the transmission belt or chain. The guard is coupled with the frame. The guard includes at least one tensioning member unitarily formed with and extending from the guard. The guard includes at least one alignment member to maintain alignment of the belt or chain to the sprocket. A biasing member is associated with the belt or chain to automatically adjust to changes in the belt or chain length to take up slack and provide positive belt or chain tension. The biasing member may be a helical spring. Further, the guard may include two tensioning members as well as two pairs of alignment members, each pair sandwiching a tension member. The handle includes a hub, a straight portion extending from the hub, a curved portion extending from the straight portion, and a knob extending from the curved portion. The knob enables rotation of the handle. The curved portion has a truncated U-shape with one end coupled with the straight portion and the knob extending from the other end. The hub has a desired height as does the straight portion, which is less than that of the hub. The curved portion has a height greater than the hub. An end of the curved portion and a side of the straight portion are continuous to form a planar side portion of the handle. A connecting member extends from the hub and is unitary with the straight portion and a portion of the curved portion. The handle may be injected molded from a plastic material.
Additional objects and advantages of the invention will be apparent from the detailed description of the preferred embodiment, and the appended claims and accompanying drawings, or may be learned by practice of the invention.